Measurement of Rice Grain Dimensions and Chalkiness, and Rice Grain Elongation Using Image Analysis

Measurements of rice grain dimensions, percent grain chalkiness, and grain elongation used to be tedious and slow due to the manual nature of measurements (e.g., use of calipers to measure grains one at a time) and the subjective nature of scoring based on visual inspection (i.e., chalkiness). Recent developments in imaging technologies have enabled more high-throughput means for measuring physical traits (i.e., grain dimensions and chalkiness) in raw grains and grain elongation by comparing ratio between raw versus cooked rice. The digital images of rice grains are captured through computer scanning and analyzed using software that can calculate area and pixel value statistics of user-defined parameters. The improvements in throughput made possible by the use of imaging technologies will allow faster quality grading of rice varieties. Market quality is usually defined based on the rice grain physical traits (grain size and shape), degree of chalkiness, and the ability of rice to elongate on cooking. In this chapter, the routine methods to measure the physical traits of rice and grain elongation using image analysis are described.